CN104942279A - Method for using polyaniline surface modification AB3 type hydrogen storage alloy - Google Patents

Abstract

The invention discloses a method for using polyaniline surface modification AB3 type hydrogen storage alloy. La0.94Mg0.06Ni3.49Co0.73Mn0.12Al0.20 alloy is prepared with the vacuum induction melting method, and after an alloy pig is mechanically smashed, particle powder with the particle diameters ranging from 200 meshes to 300 meshes is obtained after ball-milling screening; then the La0.94Mg0.06Ni3.49Co0.73Mn0.12Al0.20 and polyaniline are mixed under the conditions that the weight percentage of the La0.94Mg0.06Ni3.49Co0.73Mn0.12Al0.20 is 94%, and the weight percentage of the polyaniline is 6%; ball milling is carried out for 30-60 min under the condition that the rotating speed is 200-250 turns per minutes, and therefore the polyaniline surface modification AB3 type hydrogen storage alloy is prepared. The method is easy to operate and easy to popularize; in addition, an alloy electrode material with the good circulation performance and the excellent dynamic performance is obtained.

Description

One utilizes polyaniline surface modification AB 3the method of type hydrogen storage alloy

Technical field

The invention belongs to metallurgical chemistry and electrochemical research field, particularly one utilizes polyaniline to AB ₃type La _0.94mg _0.06ni _3.49co _0.73mn _0.12al _0.20hydrogen bearing alloy carries out the method for surface modification.

Background technology

Current commercial Ni/MH battery can not meet high-energy-density, powerful requirement, especially the demand of the power supply such as electric bicycle, electric automobile and hybrid electric vehicle.Therefore develop more high power capacity, important directions that better cyclical stability, the Ni/MH battery that more high-power and combination property is desirable are current research.So far, as novel High-capacity hydrogen storage alloy electrode material, AB ₃type R-Mg-Ni alloy (R is rare earth or Y, Ca) has been carried out large quantity research.The discharge capacity of R-Mg-Ni alloy at the temperature of gentleness is than commercial AB ₅the mixed rare earths-based alloy of type improves about 30 ~ 40%.But, because this kind of alloy surface easily forms surface film oxide, the diffusion velocity of surperficial electro catalytic activity, electric conductivity, exchange current density and hydrogen etc. are all lower, and the capacity attenuation of electrode is very fast, high-rate discharge ability is poor, and their practical application is restricted.So far, the polyaniline adopting electric conductivity good is to AB ₃type hydrogen storage alloy carries out the rarely seen report of research of surface modification.

Summary of the invention

The object of this invention is to provide one and utilize polyaniline surface modification AB ₃the method of type hydrogen storage alloy.

Thinking of the present invention: utilize the polyaniline of resistance to corrosion and excellent electric conductivity as modifier, with AB ₃type La _0.94mg _0.06ni _3.49co _0.73mn _0.12al _0.20hydrogen bearing alloy carries out surface modification by ball milling, by the modifying function of polyaniline, suppresses the corrosion of alloying component in high concentration KOH solution, improves AB ₃the cycle performance of type hydrogen storage alloy electrode.

Concrete steps are:

(1) AB is prepared by vacuum induction melting method ₃type La _0.94mg _0.06ni _3.49co _0.73mn _0.12al _0.20precursor alloy, after alloy pig mechanical crushing, with rotating speed 250 ~ 300 revs/min of ball millings 60 ~ 90 minutes, sieves out 200 ~ 300 object La _0.94mg _0.06ni _3.49co _0.73mn _0.12al _0.20alloying pellet powder.

(2) by La obtained for step (1) _0.94mg _0.06ni _3.49co _0.73mn _0.12al _0.20alloying pellet powder and polyaniline mix according to following percentage by weight: La _0.94mg _0.06ni _3.49co _0.73mn _0.12al _0.20alloying pellet powder is 94%, and polyaniline is 6%; After mixing under the rotating speed of 200 ~ 250 revs/min ball milling 30 ~ 60 minutes, the i.e. obtained AB utilizing polyaniline surface modification ₃type hydrogen storage alloy.

The inventive method is simple to operate, is easy to promote, and is beneficial to polyaniline to the Ni/MH cell negative electrode material AB with applications well prospect ₃type hydrogen storage alloy carries out surface modification, obtains the alloy electrode material with good circulation performance and excellent dynamic performance.

Detailed description of the invention

embodiment:

(1) AB is prepared by vacuum induction melting method ₃type La _0.94mg _0.06ni _3.49co _0.73mn _0.12al _0.20precursor alloy, after alloy pig mechanical crushing, with rotating speed 300 revs/min of ball millings 60 minutes, sieves out 300 object La _0.94mg _0.06ni _3.49co _0.73mn _0.12al _0.20alloying pellet powder.

(2) by La obtained for step (1) _0.94mg _0.06ni _3.49co _0.73mn _0.12al _0.20alloying pellet powder and polyaniline mix according to following percentage by weight: La _0.94mg _0.06ni _3.49co _0.73mn _0.12al _0.20alloying pellet powder is 94%, and polyaniline is 6%; After mixing under the rotating speed of 200 revs/min ball milling 60 minutes, the i.e. obtained AB utilizing polyaniline surface modification ₃type hydrogen storage alloy.

The obtained modification AB of the present embodiment is measured respectively with XRD technology, LAND 5.3B battery test system and CHI660E electrochemical workstation ₃the phase structure of type hydrogen storage alloy, cyclical stability and dynamic performance, result is as follows:

1) alloy is after polyaniline-modified process, and the maximum discharge capacity of alloy electrode is changed.Maximum discharge capacity brings up to 354.8 mAh/g by 346.4 mAh/g time unmodified.

2) alloy is after polyaniline-modified process, and cyclical stability is improved.After 50 circulations, circulation volume conservation rate is increased to 73.0% from 69.5% time unmodified, i.e. AB ₃type alloy is after polyaniline-modified process, and the cycle performance of electrode improves.

3) AB of polyaniline surface modification is utilized ₃the exchange current density of type hydrogen storage alloy, limiting current density, corrosion potential all increase, and electrode reaction resistance reduces.

In a word, the electrode adding 6% polyaniline has best comprehensive electrochemical.

Result of study confirm, the present embodiment by polyaniline to La _0.94mg _0.06ni _3.49co _0.73mn _0.12al _0.20alloy carries out surface modification, and the polyaniline-modified structure not changing precursor alloy, modified alloy is still by LaNi ₅phase and La ₂ni ₇phase composition; Polyaniline, as surface modifier, not only improves AB ₃type La _0.94mg _0.06ni _3.49co _0.73mn _0.12al _0.20the chemical property of alloy electrode, also improves the kinetic property of electrode.

Claims (1)

1. one kind utilizes polyaniline surface modification AB ₃the method of type hydrogen storage alloy, is characterized in that concrete steps are:

(1) AB is prepared by vacuum induction melting method ₃type La _0.94mg _0.06ni _3.49co _0.73mn _0.12al _0.20precursor alloy, after alloy pig mechanical crushing, with rotating speed 250 ~ 300 revs/min of ball millings 60 ~ 90 minutes, sieves out 200 ~ 300 object La _0.94mg _0.06ni _3.49co _0.73mn _0.12al _0.20alloying pellet powder;

(2) by La obtained for step (1) _0.94mg _0.06ni _3.49co _0.73mn _0.12al _0.20alloying pellet powder and polyaniline mix according to following percentage by weight: La _0.94mg _0.06ni _3.49co _0.73mn _0.12al _0.20alloying pellet powder is 94%, and polyaniline is 6%; After mixing under the rotating speed of 200 ~ 250 revs/min ball milling 30 ~ 60 minutes, the i.e. obtained AB utilizing polyaniline surface modification ₃type hydrogen storage alloy.